Pathways and biomarkers of marbling and carcass fat deposition in bovine revealed by a combination of gel-based and gel-free proteomic analyses.

Adipose tissue (AT) deposits, either intramuscular (i.e., marbling) or at the carcass level, are major economic drivers in the beef industry. To identify biomarkers and unravel mechanisms of AT deposition, we combined gel-based and gel-free methods and we mined the differential proteome of the longissimus thoracis from cows differing by two levels of both carcass and muscular adiposities (CMA). We identified 47 proteins with abundances that varied according to CMA. We listed 26 new candidate biomarkers of marbling and confirmed 21 proteins already proposed in the literature. Seven proteins involved in glycolysis or gluconeogenesis were the least abundant, while 14 proteins related to oxidative metabolism, slow-type muscle or retinoic acid metabolism were the most abundant in the high adiposity group. We highlighted eight proteins as differentially abundant and correlated with both CMA, thereby providing the first list of putative biomarkers of carcass adiposity. These proteins would be targeted in future studies aiming to categorize adiposity in cattle.